Laboratories, such as for example laboratories with bio safety level 3 and 4 (BSL 3 and BSL 4), research facilities, bio-containment suites and hospitals need autoclaves for sterilization of media, equipment and/or decontamination of waste material. Both “wet” wastes such as blood, organs, animal parts etc. and “dry” wastes such as animal cages, tools etc. are being treated in autoclaves. Essentially the autoclave shall kill dangerous microorganisms such as germs and viruses.
The pathogenic nature of the waste material from such facilities coupled with the use of the autoclave as a barrier between the facility and the outside world places special requirements on the autoclave design and processes used.
Sterilization is carried out in a manner known per se in pressure tight autoclaves, which can be charged with steam in a vacuum-steam process. In this process, the container, which are filled with the risky waste and equipments, is filled a plurality of times with steam and is then evacuated close to a vacuum level between each occasions as far as possible. After sterilization has taken place the chamber is once again evacuated, to accelerate the drying of the articles loaded inside the chamber. As pressure equalizer air is provided. The sterilized articles may now be removed.
It is very important that everything that leaves the autoclave is sterilized; not only the articles that are placed within the autoclave but also everything that leaves the autoclave via the different exhaust lines. At the top of the chamber usually an exhaust line is arranged where not condensate can be exhausted. However at the same time steam and airborne organisms may escape during the evacuation of the chamber, before they are sterile, especially under the pre-vacuum/steam process, since the vacuum device is connected to the exhaust line.
An incinerator may be arranged between the chamber and the vacuum means to enable sterilization of the steam/gas. Using incinerators is an effective and an easy way to kill organisms, since the process comprises very high temperature (several hundreds of ° C.). However, such a device may be more energy consuming and less cost effective. It is also bulky and not generally accepted.
Alternatively, a sterile filter may be used.
U.S. Pat. No. 5,480,610 discloses an apparatus and process for disinfection of waste in autoclaves and to odours neutralization of the exhaust vapours. It comprises two filters connected in series. The first filter is a prefilter and the second one is a sterile filter. The condensate produced by the filters, after disinfection is separately discharged into the waste water line.
However, for dangerous organism, disinfection is not enough and also the handling has to be done in a safe manner. Hence, there is still a need to improve the handling and safety of the medium evacuated from the chamber.